Mobile MSN Messenger messages......

On MSN Messenger 6.2, I signed up so I could get messages on my cell phone.  When does the cell phone icon show?  People have told me that when I'm signed in, it shows up blue, then other times it doesn't, and when I'm offline, it is yellow, most of the time.  Now, when I'm away, the little clock shows up, but no cell phone icon.

What's the deal with this?

Thanks beforehand.